Climatic stress index (2010) - ClimAfrica WP4

The “climatic stress index” symbolizes the pattern in 2010 of the climatic stresses (i.e. people, livestock unit or crop land) that potentially threaded the people in Africa. Strong and frequent climatic change impact the element at risk and may lead to severe consequence on food and water availability. The index results from the first and the third clusters (here combined) of the Principal Component Analysis performed among potential 10 variables. The analysis identify five dominant variables, namely “coefficient of variation for inter annual rainfall”, “probability of not exceeding 300 mm of rainfall”, “reliable annual precipitation”, “rainfall trend coefficient” and “number of year with negative Standardized Precipitation Index”, assigning a weight of 0.25 the first three variables and 0.125 for the last two variables. Before to perform the analysis the variables “coefficient of variation for inter annual rainfall” and “probability of not exceeding 300 mm of rainfall” were log transformed to shorten the extreme variation and then the five variables were score-standardized (converted to distribution with average of 0 and standard deviation of 1) in order to be comparable. All the variables are 0.5 arc-minute grids, representing the current average condition, and were produced within the ClimAfrica project. The “coefficient of variation for inter annual rainfall” is a measure of precipitation variability relative to the climatological mean precipitation. The local variation of rainfall between years gives a good indicator of where droughts are most often experienced. Similarly the “number of year with negative Standardized Precipitation Index” assesses the frequency of drought event. To calculate it, SPI 110 years maps were collected and were evaluated how many times a drought (SPI values less than - 0.5) occurred in each cells. The “probability of not exceeding 300 mm of rainfall” and the “reliable annual precipitation” are indicator of climatological rainfall average, thus important indicators of climatic stress for rain-fed based agriculture system. Finally the change (expressed by the “rainfall trend coefficient”) of rainfall during the past 110 years approximate the intensity of climate change in such period. This dataset has been produced in the framework of the “Climate change predictions in Sub-Saharan Africa: impacts and adaptations (ClimAfrica)” project, Work Package 4 (WP4). More information on ClimAfrica project is provided in the Supplemental Information section of this metadata.